SK Telecom, South Korea’s largest telecommunications company, said on Thursday that it has successfully tested its fifth generation (5G) wireless relay technology in a district packed with tall office buildings in southern Seoul.

The 5G relay repeater is used to amplify 5G wireless signals between phones and cell towers to help signals reach areas that were not accessible before. This technology significantly expands 5G network coverage areas, according to the company.

The company said the newly developed relay repeater developed together with the country’s communications equipment maker KMW can be applied to 5G network technologies by various brands and different 5G network standards.

Building a new communication network is difficult in the Gangnam office district jammed with high rises and high data traffic.

“The successful test in Gangnam has proven that our technology can be applied in other busy downtown areas,” said an official from SK Telecom, adding the 5G relay solution is expected to significantly improve 5G network service.

SK Telecom said it will continue to work with local small- and mid-sized companies to develop indigenous 5G network technologies. Recently, about 30 Korean companies agreed to take part in SK Telecom’s Request for Proposal (RFP) for 5G communications equipment introduction.